14 CEYLON PEARL OYSTER REPORT. 



margin is cut into four acute lappets ; between these the pleon segments, second to 

 fifth, are partially seen. The telsonic segment narrows near the base, forming a broad 

 oval, of which the serrate apical margin is beset with setae and small spines. 



The eyes are not large, wide apart, round. 



The short stout first antennae have the second joint of the peduncle as it were 

 embedded in the broader first joint; the tapering fiagellum is composed of seven short 

 joints, most of them carrying sensory filaments. The second antennas are about twice 

 the length of the first. The third joint of the peduncle is the longest, and not much 

 longer than broad, the fourth joint is of equal length and breadth, shorter but much 

 broader than the fifth joint and on its obliquely truncate distal margin carrying 

 some elongate setae ; one such seta is similarly situate on the fifth joint. The 

 fiagellum is shorter than the peduncle, nine-jointed. 



The mouth-parts are as in Cirolana, except that the first maxillae have four stout 

 plumose setae on the inner plate. The spines on the outer plate are slender. The 

 maxillipeds are well furnished with setae and spines, and the antepenultimate joint is 

 large. 



The first gnathopods have the second joint distally widened and the third still more 

 so, the latter having the front apex and hind margin fringed with setae. The fourth 

 joint has four blunt spines on the hind margin and a long spine on the front apex ; 

 it entirely overlaps the small fifth joint which carries two blunt spines, one of them 

 minute. The sixth joint has a stout spine between two thin ones, and some long 

 setae. The finger is slightly curved, nearly as long as the sixth joint, and, like the 

 other limbs, has on the inner margin a small tooth or spine at the base of the short 

 curved nail. 



The fourth and fifth peraeopods are nearly alike and about equal in length, but the 

 second and fourth joints are longer and the fifth and sixth joints are shorter in the 

 fifth pair than in the fourth. The side-plates are distally subquadrate in the sixth 

 peraeon segment, but are more produced and distally triangular in the seventh. 



The first pleopods have the peduncle of equal length and breadth, with four delicate 

 coupling spines. The inner ramus is rather shorter than the outer and less than half 

 as broad. Both have the rounded distal margin fringed with jelumose setae. In the 

 second pair the peduncle is broader than long ; the inner ramus is almost as long as 

 the outer and much more than half as broad. The male appendix is slender, 

 apically acute, attached just above the middle of the inner margin of the inner ramus 

 and extending considerably beyond both rami, which are armed as in the preceding 

 pair. In all five pairs the outer ramus is broad, more or less vaulted and distally 

 fringed with setae. The inner ramus has some distal setae in all but the last pair. 



The uropods have the short base of the peduncle produced on the inner side into a 

 very long process. The inner ramus is large, oval, reaching nearly to the end of the 

 telsonic segment, and having all its free margin similarly serrate and armed with 

 short spines and long plumose setae. It has two or three dark markings. The outer 



